I would not trust anything by Norton or McAfee... they are both system resource hogs and have lower than average detection rates...

For the answer to your question I would still say Kaspersky for the all in one suite. Keep in mind that Zone Alarm is right behind, but uses a few more system resources. Zone Alarm actually used Kaspersky Anti-Virus and Anti-Spyware that is licensed to them. Although they both use K9 Web Protection, Kasperskys is a little easier to configure, and has a few more options.

Don't forget about Avast! Version 4.8 that was released this weekend now also contains anti-spyware and anti-rootkit technology!